1. Field of the Invention
The present invention relates to a descaling abrading apparatus with abrading rolls and, more particularly, to a descaling abrading apparatus with abrading rolls which is employed in a steel mill, the apparatus being adapted to exfoliate a scale (oxide film) from the surface of a steel sheet (work) and abrade the descaled surface thereof by means of abrading wheels while the abrading wheels are being under pressure rotated on the steel sheet at low speed.
2. Description of the Prior Art
Conventionally, various types of scale (oxide film) which were created on the surface of a steel sheet in, for example, a steel mill were normally removed by an acid pickling system. Recently, however, the quality of steel sheets has been enhanced, which is likely to be followed by a corresponding increase in strength or toughness of the scale. This inevitably necessitates making the acid pickling rate lower according to the type of steel. As a result, it is necessary that the descaling system be so improved as to serve the purpose in the form wherein it is directly connected to a rolling line operating at a speed higher than that corresponding to the acid pickling rate. That is, there has been an increasing demand for removal of scale with higher efficiency and a corresponding increase in the rate of feeding a steel sheet. This has raised a demand for a low-cost and high-performance descaling abrading apparatus which can be substituted for the acid pickling system or can be concurrently used together with it.
Known descaling means other than the acid pickling includes elastic abrading rolls which use felted textile or the like, belt sanders, flap-type wheels (polishing and grinding wheels), wire brushes, nylon brushes which contain abrasive grains, shot blasts, liquid hones which use powdery abrasive-grain particles, etc. These known descaling means have their respective shortcomings. That is, the elastic abrading rolls are short of abrading force. The belt sanders and flap-wheels cause excessive wear although they have moderate abrading forces. The wire brushes excessively abrade a steel sheet in regard to convex portions thereof and insufficiently abrade it in regard to concave portions thereof while, on the other hand, the wires are often broken during their use. The shot blasts are unsuitable for feeding a steel sheet at high speed. The use of the liquid hones consumes an extremely large amount of electric power. The fine powders which have been produced by means of and from the abrasive grains attach onto the surface of the steel sheet, resulting often in creation of unqualified products.